Apparatus for straightening out the ends of bent pipes



May l0, 1932. l R. H. BHLING 1,857,583

APPARATUS FOR STRAIGHTENING OUT THE ENDS OF BENT PIPES Filed June 1'?, 1930 t. v 4 3, l

4, 5 C o a ji d 'patented May rc, 1932 n BID'IDOILE HIERONYIAMUS BHLING, 0F HAMBURG, GERMANY, ASSIGNOR TO FIRM ROER- GISEILLSCIlAIET. MIT BESCHBANKTER H ASETUNG, HAIVIBURG', GER.-

MANY" l' Arrm'rus ron STRAIGHTENING our 'run mms or BENT rIPEs Application mea June 17, issofserial No. 461,789, and in Germany maren s, 1980.

In producing wrought iron bentC pipes, such as elbows, bends or the like, the ends are generally not straight but curved in continuation of the curvature of the bend itself.

5 It has been proposed to straighten out the ends of such bends by the aid of a twopart mold, the two parts or dies, when closing upon one another, encompass a hollow space corresponding to the shape of th'e bend to be l produced. One of such parts is stationary and the other being movable in a4 direction parallel to the central plane of the bend, two mandrels being arranged to be forced into the ends of the bent pipe, when the movable l5 part of the mold approaches the fixed part. When thus operated upon the ends of the bend are straightened out. However, there is the drawback that the thickness of the wall of the end becomes uneven, because on lo the inner portion of the end of the bend the material is upset and is thickened, while at the outer portion the material is stretched 'and thus the wall is thinned and thus weak- I cned. This irregularity in the thickness' of 5 the wall of the pipe ends is inconvenient and even disadvantageous. Besidesrthe limited strength against inside pressure the uneven thickness of the wall makes it difficult to at- Y tach ianges or to expand the elbow ends to o form faucets or sockets or to'apply borderings. f

The object of the presentV invention is to straighten out the ends of bent pipes while maintaining uniform thickness of the wall,

5 and if for any reason an unevenness of the Y thickness of the wall exists to remove such unevenness.

The invention resides in this thatA a straightening out is effected in such manner o that to the same extent in which that portion of the wall which is on the insideof the curvature center is progressively pressedtowards the center of the opening or mouth of the bend by a mold section or jawapproaching from outside while at the same time that Y portion of the wall which is on the outside of the curvature center is pressed correspond-` ingly progressively towards the outside by a mandrel operating within the plpe agalnst u the outer part of the opening. Slnce at every moment during suchstraightening operation v the inner and the outer halves of the pipe end are pressed uniformly and simultaneously in the same direction the resistance is removed which in the known method causes an upsetting of the inner and stretching of the outer half of the pipe end.

Moreover it will be seen that the surplus materia] on the curvature inside is used up for 'supplementing that part of the material wanting or the outer curvature side, and this is done by an urging of the material beyond those lateral parts intermediate the inside and outside of the curvature.

In case the elbows or bends, the ends of which are to be straightened out, .are not uniform with regard to the thickness of the l wall an equalization of the thickness of the wall is effected by this method, an urging of the material taking place towards the weak-v er parts. If elbows and bends are to be operated upon, in which the ends have not the proper dimensions, .or are not perfectly circular, or have a slightly too large cross-section the method will have the result of a calibration ofthe pipe ends.

An apparatus for carrying out the method mentioned above may consist of a mandrel and jaws or halves of a mold, which mandrel is given 'a pivotal movement on the movable j aw closing down. The pivotal movement of the mandrel is lcarried ont in such manner that it presses the outer half of the pipe end outwardly, which is done at the same time when the inner half of the pipe end is pressed in the same direction by the movable jaw.

On completing this operation the axis of the mandrel will be in a position tangentially to the central@l curvature line, corresponding to the central line of the straightened end of the bend. The' end is thus straightened out.

By way of example in tha/drawings so much ofY an apparatus is shown diagram-v matically as is necessary tofillustrate the invention.

Fig. 1 is a vertical section of part of the apparatus in a position in which the movable jaw is in upperpositon, thus the mold being open.

Fig. 2 is an elevation of the same parts of the apparatus in closed position.

Fig. 3 is a section drawn to the line 3-3 of i Fig. 1, and

adapted to be used for bends having a not `true clrcular cross-section or a wall of uneven thickness.

As shown in the drawings the mandrel a t' iS.. formed by a short cylinder provided with a shaft or handle b at its end. The diameter of the c lindrical mandrel a corresponds to the inner diameter of the bend or pipe end c, so'that it can be introduced into such end. The bend c, the end of which is to be straightened out, is placed into the open mold, that is to say between the fixed jaw d and the movable jaw e in such manner, that its end abuts against the shoulder f on the jaw e. The mandrel a is subsequently or previously introduced into the bend so as to contact with its front edge against the outer part of the wall at the place inside the bend where the straightened part after being operated upon is to commence. Moreover the mandrel also contacts with its cylindrical part with `the edge of the wall of the outer side curvature and moreover on the opposite side lalso with the inner side curvature of the bend.

When the jaw e is moved towards the fixed j aw d the mandrel is oscillated about a point where its front edge contacts inside the'tube with the outer part of the curvature asla pivot, which pivot point is designated by Fig. 1. The pivotal movement of the mandrel is effected in the construction shown whereby the lateral shoulder fof .the jaw e contacts with that part of the mandrel a projecting out fromA the end of the bent pipe,

and thus bycorresponding movement of thejawv e a pivotal movement of the mandrel is eected about the pivot w. Hereby the jawl 'e tends to press the wall designated by y of the inner curved part ofthe tube end downwards towards the mandrel a, the latter at the same time pressing outwardly that part of the outer curved wall of the pipe which is designated'by z. This operation is carried on progressively until the jaws e and d vare closed upon one another, and the axis of the` mandrel a forms the continuation of the cen- 'tra1 line of curvature tangentially, as maybe vbe gradually urged `further on towards the outer side of the curvature. Even if theendV of the bent pipe is not properly dimensioned or not round in cross-sect1on or has an unequal thickness of the wall, the pipe end will be given the proper section as will be understood from Figs. 6 and 7, the Wallv being equalized throughout.

The mandrel a of course might be moved or pivoted independently from the movement of the jaw e by any desired means.

I claim `1. An apparatus for straightening the ends of bent pipes, elbows, bends, or the like, comprising two concave 'j aws, one being fixed and the other movable towards the fixed aw, a pivotally movable mandrel havingla cylindrical part of a cross-section corresponding to the inner cross-section of the pipe and when inserted into the end of the bent pipe contacting with its outer edge the outer part of the bent pipe, where Vthe straight end is to commence and with its cylindrical part on one side the edge of the outer side curvature,

and on the opposite side the inner side curvature of the bend, the first mentioned place of contact forming the pivot point about which the mandrel is pivoted.

2. An apparatus for straightening the ends of bent pipes, elbows, bends or the like, comprising two concave jaws, one being fixed and the other movabl towards the fixed aw, a pivotally movable mandrel having a cylindrical part ofia cross-section corresponding vto the inner cross-section'of the pipe andwhen inserted into the end of the bent pipe contactingl with'its outer edge the outer art of the bent pipe, where the straight end 1s to commence, and with its cylindrical part on roneside the edge of the outer side curvature and on the opposite side the inner side curvature of the bend, the irstmentioned place of'` contact forming the pivot point about which the mandrel is moved, the mandrel also contacting the movable jaw to be operated thereby when' this jaw moves towards the other jaw.

3. An 'l apparatus for straightening the ends of bent pipes, elbows, bends or the like,

comprising a fixed jaw, a movable jaw and a mandrel, adapted to be inserted into the end of the bent pipe 'and to be pivoted after being inserted by the movable jaw engaging 4. An apparatus according to claimjl, the

movable 'jaw `beingrprovided with. an inner shoulder; against which the .bent pipe bears' with its edge on Athe curvature inner. side when being. operated on.

`In Ntestimony whereof name' to this specification.

I havesigned my` 

